Motorcycle frame



FIG. 1 is a perspective view showing my new design;

FIG. 2 is a right side view of FIG. 1;

FIG. 3 is a left side view of FIG. 1;

FIG. 4 is a top side view of FIG. 1;

FIG. 5 is a front side view of FIG. 1; and,

FIG. 6 is a rear side view of FIG. 1.

The portions shown in broken lines form no part of the claimed design. 

The ornamental design for a motorcycle frame, as shown and described. 